Aramid yarn having excellent adhesive properties with polyurethane matrix resin, method for producing the same and aramid fabric produced therefrom

ABSTRACT

An aramid yarn which is adhesive to a polyurethane matrix resin is disclosed. The polyurethane resin is adhered and impregnated to the surface and inside of the aramid yarn, and the content of the polyurethane resin is 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated. An aramid fabric is woven into a basket-weave structure and thus has low denseness, the wetting property with the polyurethane matrix resin which is impregnated into the aramid fabric is improved, and consequently, the adhesive properties between the aramid fabric and the polyurethane matrix resin are improved.

TECHNICAL FIELD

The present invention relates to an aramid yarn having excellent adhesive properties with a polyurethane matrix resin, a method for producing the same, and an aramid fabric produced therefrom. More particularly, the present invention relates to an aramid yarn which has an excellent wetting property with a polyurethane matrix resin, can improve adhesive properties between polyurethane matrix resins when used as a reinforcing fiber for a fiber/resin composite material, and thus is useful as refrigerator insulation materials, automotive component materials, and electronic component materials, a method for producing the same, and an aramid fabric produced therefrom.

BACKGROUND ART

As a heat-insulating material for electronic products such as refrigerators, a heat-insulating material in which a ceramic material adheres to a composite material composed of reinforcing fiber material and polyurethane matrix resin has been widely used.

The reinforcing fiber material is used in the form of yarn, and is also used in the form of a fabric woven from the yarn.

In prior arts, glass fiber has been used as the reinforcing fiber material, but there were problems that the glass fiber has a high specific gravity, which makes it difficult to reduce the weight and is harmful to the human body.

In another prior art, carbon fiber has been used instead of glass fiber as the reinforcing fiber material, but there were problems that the carbon fiber has high specific stiffness and thus causes deterioration in processability and impact resistance.

In yet another prior art, aramid yarn or plain weave aramid fabric was used as the reinforcing fiber material, but there was a problem that adhesive properties between aramid yarn or plain weave aramid fabrics and polyurethane matrix resins are decreased and that the plain weave aramid fabric has a dense structure and thus a poor wetting property with the polyurethane matrix resin.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

It is an object of the present invention to provide an aramid yarn and an aramid fabric which can improve adhesive properties between polyurethane matrix resins when used as a reinforcing fiber at the time of producing a composite material composed of a reinforcing fiber and a polyurethane matrix resin and thus are useful as refrigerator insulation materials, automotive component materials, electronic component materials, and the like.

Technical Solution

In one embodiment of the present invention, in order to enable an aramid yarn, which is a reinforcing fiber of the composite material, to adhere well to a polyurethane resin, which is a matrix resin of the composite material, while adhering and impregnating the polyurethane resin to the surface and inside of the aramid yarn, the adhesion and impregnation amount of the polyurethane resin is adjusted to 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated.

Advantageous Effects

The aramid yarn according to the present invention is excellent in adhesive properties with the polyurethane matrix resin when used as a reinforcing fiber for a fiber/resin composite material due to a sizing agent composition adhered and impregnated to the surface and inside of the aramid yarn.

In the present invention, since the sizing agent composition can be adhered and impregnated to the aramid yarn during a spinning step of producing the aramid yarn, a separate step of adhering the sizing agent composition can be omitted.

Moreover, since the aramid fabric according to the present invention is woven into a basket-weave structure and thus has low denseness, the wetting property with the polyurethane matrix resin impregnated into the aramid fabric is improved, and consequently, the adhesive properties between the aramid fabric and the polyurethane matrix resin are improved.

The present invention is useful as a refrigerator insulation material, an automotive component material, an electronic component material, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process schematic diagram of producing the aramid yarn according to the present invention.

FIG. 2 is a weave structure of an example of the aramid fabric according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

The aramid yarn according to the present invention is characterized in that a polyurethane resin is adhered and impregnated to the surface and inside of the aramid yarn, and the content of the polyurethane resin is 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated.

The content of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn is 1.5 to 7.0% by weight, preferably 2 to 5% by weight, more preferably 3 to 5% by weight, based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated. Within these content ranges, it is desirable to maintain the intrinsic physical properties of the aramid yarn as they are and improve the production process while improving the adhesive properties with the polyurethane matrix resin.

The polyurethane resin is preferably a reaction product of polytetramethylene ether glycol and isophorone diisocyanate.

As shown in FIG. 1, the method for producing an aramid yarn according to the present invention is characterized in that, during continuous processes of producing an aramid yarn by spinning, coagulating, washing, drying, and heat-treating an aramid spinning dope containing an aramid resin and a solvent, while adhering and impregnating a sizing agent composition composed of a polyurethane resin, an organic solvent, and water to the surface and inside of the aramid yarn, the content of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn is adjusted to 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before polyurethane resin is adhered and impregnated.

The sizing agent composition is preferably composed of 35 to 45% by weight of a polyurethane resin, 2 to 5% by weight of an organic solvent, and 55 to 63% by weight of water, in order to improve adhesive properties with the polyurethane matrix resin.

As one example of the sizing agent composition, a sizing agent composition composed of 35 to 45% by weight of polyurethane, which is a reaction product of polytetramethylene ether glycol and isophorone diisocyanate, 2 to 5% by weight of N-methyl pyrrolidone, and 55 to 63% by weight of deionized water may be used.

As another example, during the process of spinning an aramid yarn by extruding an aramid spinning dope in the form of monofilaments through spinneret holes and then converging the extruded monofilaments in the form of a multifilament with a converging roller, a sizing agent composition is supplied to the surface of a converging roller 40 to adhere and impregnate the sizing agent composition to the surface and inside of the aramid yarn that is converged in the form of multifilament.

As shown in FIG. 1, the aramid yarn is typically produced by a method including the steps of extruding an aramid spinning dope in the form of monofilaments through the extruding holes formed in a spinneret 10, passing the extruded monofilaments through a coagulation bath 20 and a coagulation jet tube 30 in this order, converging the monofilaments in the form of a multifilament by a converging roller 40, subsequently subjecting to washing, drying, and heat treatment while passing through a washing roller 50, a drying roller 60, and a heat treatment roller 70, and winding the resultant yarn by a take-up roller 80.

In the present invention, when producing the aramid yarn by the above-mentioned method, the sizing agent composition is supplied to the surface of the converging roller 40, and the sizing agent composition is adhered and impregnated to the surface and inside of the aramid yarn.

The content of the polyurethane resin which is adhered and impregnated to the surface and inside of the aramid yarn is adjusted to 1.5 to 7.0% by weight, preferably 2 to 5% by weight, more preferably 3 to 5% by weight, based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated.

When the content of the polyurethane resin is less than 1.5% by weight, the effect of improving the adhesive properties with the polyurethane matrix resin is weakened. When the content of the polyurethane resin is greater than 7.0% by weight, spinning and weaving process properties are deteriorated, the yarn may become stiff, and the physical properties may be deteriorated.

In the present invention, since the sizing agent composition is adhered/impregnated to the aramid yarn during a continuous process of producing an aramid yarn, preferably during the spinning step, it is not necessary to perform a separate step of adhering the sizing agent composition after the production of the aramid yarn.

An aramid fabric according to the present invention is characterized in that a warp and a weft are composed of aramid yarn wherein a polyurethane resin is adhered and impregnated to the surface and inside of the aramid yarn, and the content of the polyurethane resin is 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated.

It is desirable that the warp and the weft are woven into a basket-weave structure to improve the wetting property of the aramid fabric to the polyurethane matrix resin.

As an example of the basket-weave structure, a 4×4 basket-weave structure or the like as shown in FIG. 2 can be used.

The fineness of each of the warp and the weft is 1000 to 3000 denier, and the warp density and the weft density are preferably 10 to 20 epi (end per inch), respectively, to appropriately reinforce the physical properties of the composite material and the final electronic insulation component.

The aramid yarn according to the present invention is excellent in adhesive properties with the polyurethane matrix resin when used as a reinforcing fiber for a fiber/resin composite material due to a polyurethane resin adhered or impregnated to the surface and inside of the aramid yarn.

In the present invention, since the sizing agent composition composed of a polyurethane resin, an organic solvent, and water can be adhered and impregnated to the aramid yarn during the spinning step of producing the aramid yarn, a separate step of adhering the sizing agent composition can be omitted.

Moreover, since the aramid fabric according to the present invention is woven into a basket-weave structure and has low denseness, the wetting property with the polyurethane matrix resin impregnated into the aramid fabric is improved, and consequently, the adhesive properties between the aramid fabric and the polyurethane matrix resin are improved.

The present invention is useful as a refrigerator insulation material, an automotive component material, an electronic component material, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

The following examples are preferred embodiments of the present invention and the protection scope of the present invention is not limited only thereto.

Example 1

As shown in FIG. 1, a sizing agent composition composed of 36 wt % of polyurethane, which is a reaction product of polytetramethylene ether glycol and isophorone diisocyanate, 4 wt % of N-methyl pyrrolidone, and 60 wt % of deionized water was supplied onto the surface of the converging roller for converging aramid monofilaments in the form of a multifilament when spinning an aramid yarn. While adhering/impregnating the sizing agent composition to the aramid yarn passing through the converging roller, the content of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn was adjusted to 3 wt % based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin was adhered and impregnated. Thereby, 3000 denier aramid yarn was produced.

Next, the aramid yarn adhered and impregnated with the polyurethane resin as described above was used as a warp and a weft to weave an aramid fabric into a 4×4 basket-weave structure.

At this time, the warp density and the weft density were set to 13 epi (end per inch), respectively.

The aramid fabric woven as described above was impregnated with a polyurethane resin (matrix resin) to produce a reinforcing material for heat insulation.

At this time, the impregnation amount of the polyurethane resin (matrix resin) was 35 wt % based on the sum of the reinforcing material for heat insulation.

The breaking strength of the reinforcing material for heat insulation produced as described above was measured in accordance with ASTM Test Method D 3039, and as a result, it exhibited excellent breaking strength of 980 MPa.

Example 2

As shown in FIG. 1, a sizing agent composition composed of 42 wt % of polyurethane, which is a reaction product of polytetramethylene ether glycol and isophorone diisocyanate, 4 wt % of N-methyl pyrrolidone, and 54 wt % of deionized water, was supplied onto the surface of the converging roller for converging aramid monofilaments in the form of a multifilament when spinning an aramid yarn. While adhering/impregnating the sizing agent composition to the aramid yarn passing through the converging roller, the content of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn was adjusted to 5 wt % based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin was adhered and impregnated. Thereby, 1500 denier aramid yarn was produced.

Next, the aramid yarn adhered and impregnated with the polyurethane resin as described above was used as a warp and a weft to weave an aramid fabric into a 4×4 basket-weave structure.

At this time, the warp density and the weft density were set to 20 epi (end per inch), respectively.

The aramid fabric woven as described above was impregnated with a polyurethane resin (matrix resin) to produce a reinforcing material for heat insulation.

At this time, the impregnation amount of the polyurethane resin (matrix resin) was 35 wt % based on the sum of the reinforcing material for heat insulation.

The breaking strength of the reinforcing material for heat insulation prepared as described above was measured in accordance with ASTM Test Method D 3039 and as a result, it exhibited an excellent breaking strength of 972 MPa.

Comparative Example 1

3000 denier aramid yarn was dipped into a bath containing a sizing agent composition composed of 20 wt % of polyurethane, which is a reaction product of polytetramethylene ether glycol and isophorone diisocyanate, and 4 wt % of N-methyl pyrrolidone and 76 wt % of deionized water. Then, while squeezing the dipped yarn with a roller squeegee, the content of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn was adjusted to 1 wt % based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before polyurethane resin was adhered and impregnated. Thereby, 3000 denier aramid yarn was produced.

Next, the aramid yarn adhered and impregnated with the polyurethane resin as described above was used as a warp and a weft to weave an aramid fabric into a plain weave structure.

At this time, the warp density and the weft density were set to 13 epi (end per inch), respectively.

The aramid fabric woven as described above was impregnated with a polyurethane resin (matrix resin) to produce a reinforcing material for heat insulation.

At this time, the impregnation amount of the polyurethane resin (matrix resin) was 35 wt % based on the sum of the reinforcing material for heat insulation.

The breaking strength of the reinforcing material for heat insulation produced as described above was measured in accordance with ASTM Test Method D 3039, and as a result, it exhibited inferior breaking strength of 760 MPa.

Comparative Example 2

An aramid yarn, an aramid fabric, and a reinforcing material for heat insulation, which were impregnated and adhered with a polyurethane resin, were produced in the same manner as in Example 1, except that in Example 1, the content of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn was changed to 7.5% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin was adhered and impregnated.

The breaking strength of the reinforcing material for heat insulation produced as described above was measured in accordance with ASTM Test Method D 3039, and as a result, it exhibited inferior breaking strength of 820 MPa.

Comparative Example 3

An aramid fabric was woven into a plain weave structure by using 3000 denier aramid fibers not treated with a sizing agent composition as a warp and a weft.

The warp density and the weft density were set to 13 epi (end per inch), respectively.

The aramid fabric woven as described above was impregnated with a polyurethane resin (matrix resin) to produce a reinforcing material for heat insulation.

The content of the polyurethane resin (matrix resin) was adjusted to 35% by weight based on the sum of the reinforcing material for heat insulation.

The breaking strength of the reinforcing material for heat insulation produced as described above was measured in accordance with ASTM Test Method D 3039, and as a result, it exhibited inferior breaking strength of 780 MPa.

In the present invention, the content (wt %) of the polyurethane resin adhered and impregnated to the aramid yarn was measured by the following method.

First, 2.5 g of an aramid yarn (hereinafter referred to as “sample”) in which an organic solvent and water in the sizing agent components were volatilized and only a polyurethane resin was adhered and impregnated to the surface and inside of the aramid yarn was prepared. Then, the sample was inserted into a syringe-shaped cylindrical tube, to which about 8 ml of methanol was added so that the sample was sufficiently wetted, and then pressure was repeatedly applied to the tube until no more solvent was released.

Next, the operation of adding about 8 ml of methanol to the tube again and repeatedly applying pressure to the tube until no more solvent was released was further repeated two times. Then, the sample was removed from the tube and dried at 110° C. to measure the weight (WO) of the aramid yarn in which the polyurethane resin was not adhered and impregnated to the surface and inside.

Next, the weight of the aramid yarn (W1: sample weight) in which only the polyurethane resin in the sizing agent composition was adhered and impregnated to the surface and inside and the weight (WO) of the aramid yarn in which the polyurethane resin in the sizing agent composition was not adhered and impregnated to the surface and inside were substituted into the following equation to determine the content (W) of the polyurethane resin adhered and impregnated to the surface and inside of the aramid fiber.

$W = {\left( \frac{{W\; 1} - {W\; 0}}{W\; 1} \right) \times 100}$

[Industrial Applicability] INDUSTRIAL APPLICABILITY

According the present invention, a composite material which is composed of reinforcing fibers and polyurethane matrix resins and is thus useful as a heat-insulating material for electronic products is used as a reinforcing fiber material that improves adhesive properties between the reinforcing fiber and the polyurethane matrix resins. 

1. An aramid yarn having excellent adhesive properties with a polyurethane matrix resin characterized in that the polyurethane resin is adhered and impregnated to the surface and inside of the aramid yarn, and the content of the polyurethane resin is 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated.
 2. The aramid yarn having excellent adhesive properties with a polyurethane matrix resin according to claim 1 characterized in that the aramid yarn is in the form of a multifilament consisting of a plurality of monofilaments.
 3. The aramid yarn having excellent adhesive properties with a polyurethane matrix resin according to claim 1 characterized in that the polyurethane resin is a reaction product of polytetramethylene ether glycol and isophorone diisocyanate.
 4. A method for producing an aramid yarn having excellent adhesive properties with a polyurethane matrix resin characterized in that, during continuous processes of producing an aramid yarn by spinning, coagulating, washing, drying, and heat-treating an aramid spinning dope containing an aramid resin and a solvent, while adhering and impregnating a sizing agent composition composed of a polyurethane resin, an organic solvent, and water to the surface and inside of the aramid yarn, the content of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn is adjusted to 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated.
 5. The method for producing an aramid yarn having excellent adhesive properties with a polyurethane matrix resin according to claim 4, characterized in that, during the process of spinning the aramid yarn by extruding an aramid spinning dope in the form of monofilaments through spinneret holes and then converging the extruded monofilaments in the form of a multifilament with a converging roller, a sizing agent composition is supplied to the surface of the converging roller to adhere and impregnate the sizing agent composition to the surface and inside of the aramid yarn that is converged in the form of multifilament.
 6. The method for producing an aramid yarn having excellent adhesive properties with a polyurethane matrix resin according to claim 4, characterized in that the sizing agent composition is composed of 35 to 45% by weight of a polyurethane resin, 2 to 5% by weight of an organic solvent, and 55 to 63% by weight of water.
 7. The method for producing an aramid yarn having excellent adhesive properties with a polyurethane matrix resin according to claim 4, characterized in that the water is deionized water.
 8. The method for producing an aramid yarn having excellent adhesive properties with a polyurethane matrix resin according to claim 4, characterized in that the polyurethane resin is a reaction product of polytetramethylene ether glycol and isophorone diisocyanate.
 9. An aramid fabric having excellent adhesive properties with a polyurethane matrix resin characterized in that a warp and a weft are composed of aramid yarn, wherein a polyurethane resin is adhered and impregnated to the surface and inside of the aramid yarn, and the content of the polyurethane resin is 1.5 to 7.0% by weight based on the sum of the weight of the polyurethane resin adhered and impregnated to the surface and inside of the aramid yarn plus the weight of the aramid yarn before the polyurethane resin is adhered and impregnated.
 10. The aramid fabric having excellent adhesive properties with a polyurethane matrix resin according to claim 9, characterized in that the warp and the weft are woven into a basket-weave structure.
 11. The aramid fabric having excellent adhesive properties with a polyurethane matrix resin according to claim 9, characterized in that the fineness of each of the warp and the weft is 1000 to 3000 denier, and the density of each of the warp and the weft is 10 to 20 epi (end per inch). 